Energy Loss in Steep Open Channels with Step-Pools

Thappeta, Suresh Kumar; Bhallamudi, S. Murty; Chandra, Venu; Fiener, Peter; Baki, Abul Basar M.

doi:10.3390/w13010072

Cited by 9 publications

(3 citation statements)

References 40 publications

(92 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the homogenous mixture of multiphase flows, such as a flow moving through an open channel with a mixture of air and water in a rectangular coordinate system, ANSYS CFX commercial model (ANSYS, 2013) was applied in this study. This model has been widely applied to simulate various types of water flow in open channels, such as flow around a halfsubmerged cylinder in an open channel (Alamayreh et al, 2021), energy loss in steep open channels (Thappeta et al, 2021), design of contractions in supercritical flow open channels (Martinez and Niño, 2020). The numerical scheme of this model is the finite volume method, which divides the computational domain inti small cells for obtaining solutions by assigning a boundary condition to each cell, and the complete set of governing equations for an incompressible multiphase flow model is as follows:…”

Section: Numerical Simulations 31 Ansys Cfx Modelmentioning

confidence: 99%

Experimental and numerical investigation of water-surface characteristics at crossing connected non-orthogonally to four flat channels

Jeong

2021

Journal of Hydrology and Hydromechanics

View full text Add to dashboard Cite

Most studies on the flood flow characteristics at a crossing focus on channels connected orthogonally or at right angle, but studies on non-orthogonally connected channels remain limited. In this study, hydraulic-model experiments and numerical simulations are performed to analyze the characteristics of the water-surface variation in and around a crossing connected non-orthogonally to four flat channels. Comparison of the measured and simulated water depth distributions in and around the crossing indicates that the results are in relatively good agreement. In the experiment where the angle between two upstream channels is 45°, the water flow pattern in and around the crossing corresponds approximately to Type I proposed by Mignot et al. (2008). However, it was found that there is no any flow type to correspond to the water flow pattern measured in the case of the angle of 135°. For analyzing the variation of the water depth in and around the crossing with inflow, numerical simulation is performed by setting the inflow ratio of the two inlet channels to one, three, and six, respectively.

show abstract

Section: Numerical Simulations 31 Ansys Cfx Modelmentioning

confidence: 99%

Experimental and numerical investigation of water-surface characteristics at crossing connected non-orthogonally to four flat channels

Jeong

2021

Journal of Hydrology and Hydromechanics

View full text Add to dashboard Cite

show abstract

“…Understanding empirically the importance of randomness of roughness elements in the head loss models is still necessary. However, nowadays, the flow resistance due to the presence of roughness elements has been studied widely using 3D computational fluid dynamics (CFD) models [25,26,28].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Head Loss Due to Cluster of Randomly Distributed Non-Uniform Roughness Elements in Supercritical Flow

Thappeta

Fiener

Chandra

2022

Water

Self Cite

View full text Add to dashboard Cite

Accurate estimation of head loss introduced via randomly placed roughness elements found in natural or constructed streams (e.g., fish passages) is essential in order to estimate flow variables in mountain streams, understand formation of niches for aquatic life, and model flow structure. Owing to the complexity of the involved processes and the often missing detailed data regarding the roughness elements, the head loss in such streams is mostly approximated using empirical models. In our study, we utilize flume experiments to analyze the effects of the spatial distribution of roughness elements on water surface levels and head loss and, moreover, use the produced data to test three empirical models estimating head loss. The experiments were performed in a 15 m long, 0.9 m wide flume with a slope of 5% under large Froude numbers (2.5–2.8). Flow velocities and water levels were measured with different flow rates at 58 points within a 3.96 m test section of the flume. We could show that different randomly arranged patterns of roughness elements significantly affected head loss (differences up to 33.6%), whereas water jumps occurred when flow depths were in the same size range as the roughness elements. The roughness element position and its size influenced water surface profiles. None of the three tested empirical models were able to well reproduce the differences in head loss due to the different patterns of roughness elements, with overestimated head loss from 12 to 94.7%, R2 from 41 to 73%, NSE from −21.1 to 0.09, and RRMSE from 18.4 to 93%. This generally indicates that these empirical models are conditionally suitable to consider head loss effects of random patterns of roughness elements.

show abstract

“…Guenther et al [25] studied the characteristics of flow (i.e., aeration concentration and vortex characteristics) and rate of energy dissipation with different types of stepped spillways. Other researchers such as Ghaderi et al [26], Hekmatzadeh et al [27], Bayon et al [28], and Thappeta et al [29] performed numerical solutions to modeling flows over spillways.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of the Effects of Geometric Appendance Elements on Energy Dissipation over Stepped Spillway

Ghaderi

Abbasi

2021

Water

View full text Add to dashboard Cite

In the stepped spillway, the steps, by providing an artificial roughening bed, dissipate the flow of energy more than other types of spillways, so the construction costs for stilling basin are reduced. However, what is important in this type of spillway is increasing the effectiveness of steps in the rate of energy dissipation. The present study deals with experimental and numerical simulations regarding the influence of geometric appendance elements on the steps and its impact on the energy dissipation performances, flow patterns properties, turbulent kinetic energy, flow resistance and the Darcy roughness. The localization of inception point of air entrainment is also assessed. To this aim, different configurations are taken into account. The computational procedure is validated with experimental results and then used to test the hydraulic behavior of different geometric configurations. The results showed that the appendance elements on the steps increased the turbulent kinetic energy (TKE) values and Darcy–Weisbach friction and the energy dissipation increased significantly. By reducing the height of the elements, energy dissipation and the TKE value increase more significantly. With the appendance elements on step, the air entrainment inception locations a positioning further upstream than the flat step stepped spillway.

show abstract

Energy Loss in Steep Open Channels with Step-Pools

Cited by 9 publications

References 40 publications

Experimental and numerical investigation of water-surface characteristics at crossing connected non-orthogonally to four flat channels

Experimental and numerical investigation of water-surface characteristics at crossing connected non-orthogonally to four flat channels

Experimental Study on Head Loss Due to Cluster of Randomly Distributed Non-Uniform Roughness Elements in Supercritical Flow

Experimental and Numerical Study of the Effects of Geometric Appendance Elements on Energy Dissipation over Stepped Spillway

Contact Info

Product

Resources

About